[GHC] #8331: GHC fails to apply {-# SPECIALIZE #-} for dubious reasons

[GHC]

#8331: GHC fails to apply {-# SPECIALIZE #-} for dubious reasons
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              Reporter:  blitzcode   |             Owner:
                  Type:  bug         |            Status:  new
              Priority:  normal      |         Milestone:  7.10.1
             Component:  Compiler    |           Version:  7.8.3
            Resolution:              |          Keywords:
Differential Revisions:              |  Operating System:  Unknown/Multiple
          Architecture:              |   Type of failure:  Incorrect
  Unknown/Multiple                   |  warning at compile-time
            Difficulty:  Unknown     |         Test Case:
            Blocked By:              |          Blocking:
       Related Tickets:              |
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Comment (by rwbarton):

 Replying to [comment:4 blitzcode]:
 > I'm afraid, I can't. I was able to build HEAD, but I don't know how to
 setup a package db containing mtl for it so I can compile the snippet.

 Use `cabal install -w .../ghc/inplace/bin/ghc-stage2 mtl`.

 The "RULE left-hand side too complicated to desugar" warning seems to no
 longer trigger with HEAD, at least.

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/8331#comment:5>
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